BRS 305 sorghum bran and its extract present a high phenolic profile and high antioxidant activity in vitro, and reduce oxidative stress in vivo

This study evaluated the chemical composition and in vitro antioxidant activity of sorghum bran, extruded whole-grain sorghum, and a dry phenolic extract from sorghum bran, and evaluated the dry phenolic extract from sorghum bran toxicity and oxidative stress resistance using nematode model (C. elegans). Sorghum bran presented higher content of moisture, ash, lipid, total and insoluble fiber, resistant starch, condensed tannins, total phenolics, flavonoids, anthocyanins, free and bound phenolic acids, and in vitro antioxidant activity compared to extruded sorghum. Extrusion reduced bioactive compound content and antioxidant capacity. Dry phenolic extract remained a source of phenolics with strong antioxidant activity. Also, it presented hormetic behavior, being pro-oxidant in high doses and an antioxidant in appropriate doses, in the toxicity and resistance stress test. Concentrations up to 0.4 μM were safe for C. elegans, whereas 4 μM reduced survival. Therefore, sorghum bran and its extract have potential for developing functional products.